1. Field of the Invention
The present invention is directed to a mold. The present invention is also (Erected to a device for processing the same, and a replica made therefrom.
2. Background
Liquid crystal display known as LCD is an electronic device that changes electrical signals to visual signals by using the change of transmittance of liquid crystals according to applied voltages.
Generally, liquid crystal display comprises a liquid crystal panel displaying an image corresponding to driving signal and data signal from outside, and a backlight unit disposed at a back side of the liquid crystal panel for illuminating the panel.
The backlight unit comprises light source, reflection sheet and optical film.
The light source generates a light having a certain wavelength.
The reflection sheet reflects a light generated from the light source to proceed toward the liquid crystal panel.
The optical film comprises diffusion sheet, prism sheet and protective sheet.
The light generated from the light source passes through the diffusion sheet. Here, the diffusion sheet scatters the incident light to prevent its partial concentration and make the brightness uniform.
The brightness of the light transmitted from the diffusion sheet rapidly decreases. So, the prism sheet is used to prevent the decrease of brightness.
FIG. 1 is a view illustrating a conventional method of processing a mold.
Referring to FIG. 1, a bite 100 to which diamond particles 100a are adhered is fixed to a table and, a mold 110 is disposed under the bite 100, and a surface of the mold 110 contacts with the bite 100.
And, the mold 110 rotates, and moves to a left direction, and processes the bite 100. Here, the bite 100 may move horizontally when the mold 110 rotates only.
Generally, the rotation speed and straight line movement speed of the bite 100 are constant. Therefore, the surface of the mold 110 is cut by certain amount, and a linear uniform surface 112 is obtained, as shown in FIG. 1.
FIG. 2 is a perspective view illustrating a prism sheet manufactured by using the mold of FIG. 1.
Referring to FIG. 2, the prism sheet 200 comprises a prism base 230, and an array of prisms 210 formed on the prism base 230. The prisms 210 include side surfaces composed of a first surface 212 and a second surface 214, and the shape of prisms 210 is approximately isoscelestriangle. Generally, the first surface 212 and the second surface 214 make a right angle, but may make other angles by selection.
A plurality of prisms 210 are disposed on the prism base 230, and peaks 216 and grooves 218 are formed in turn. The prism sheet 200 makes a light incident from the prism base 230 refract by passing it through the prisms 210. Accordingly, the incident light with low incident angle is focused to front side, whereby the brightness is enhanced within a valid angle of view.
However, these prisms 210 of the conventional prism sheet 200 refract the incident light toward one direction because their surfaces are flat. Therefore, the conventional prism sheet 200 has a disadvantage that it is not appropriate to refract the light in two dimensions.